The present invention is directed to protective assemblies for food and non-food objects. The assemblies are designed to preserve food products, such as pizza, and also can be used in other fields such as the packaging of boiled or steamed medical instruments and the packaging of mechanical or electrical parts which have been washed in a hot solvent bath as an intermediate step prior to packaging.
When materials or objects are heated or washed in a hot bath, if not used immediately after being prepared, they often must be protected in some way as they are stored and/or transported to their destination. In the case of food stuffs which are cooked by heating, it is important that the protective container assembly protect the quality and cleanliness of the prepared food stuffs.
When food stuffs are cooked by any of several means, including microwave energy, boiling, steaming, frying and deep frying, the primary intent is to kill any latent bacteria and convert the food stuff from a "raw" product to a "cooked" product. Often when the cooking process is completed, the food stuff gives off residual liquids and volatiles. The most common liquids which exude are greases, oils and water while the most common volatile is moisture vapor.
Moisture vapor, such as steam, is lighter than air and moves upwardly while the liquids, being influenced by gravity, normally move downwardly.
When one refers to the "quality" of a cooked food, it generally implies that the food should be hot and contain the proper amount of moisture. If it is too cold, too soggy or too dry, it is viewed to have less than the desired quality. If the food stuff cannot be served immediately after cooking, and is not properly protected, the juices and condensate can contact it and cause it to become soggy. If the steam vapors are vented away too rapidly and the food stuff becomes cold, then it also does not maintain the desired quality when served. Additionally, a protective container assembly must protect the food stuffs from outside sources of contamination if the food stuffs are to be handled and transported.
U.S. Pat. No. 4,707,883 discloses an envelope made from a composite material where a foamed polyethylene is positioned between two layers of the polyethylene film. While this type of prior art structure tends to retard heat loss, it does not solve the moisture problem which results from condensation. With respect to pizzas specifically, if the steam leaving the pizza is allowed to condense, it is possible that the container will become damp and condensed water droplets will fall back on the pizza resulting in an unappetizing product.
U.S. Pat. No. 4,058,214 attempts to solve the steam condensation problem by venting the overall carrying and insulating enclosure. However, steam venting allows much of the heat to escape, thus lowering the temperature of the object being carried.
Other prior art patents also disclose protective assemblies for protecting cooked food. Grease absorbing underpads are disclosed in U.S. Pat. Nos. 4,923,729, 4,935,276 and 4,935,282.
U.S. Pat. No. 4,861,632 discloses a laminated bag which is a multilayered structure. Each side of the bag includes an apertured inner sheet having a plurality of perforations, an outer moisture impervious thermoplastic film sheet and an absorbent layer interposed between the two sheets. The absorbent layer is disclosed as preferably consisting of sheets of paper toweling. The inner apertured sheet is a flat film which allows for the entrance of either fluids or vapors. When the food rests on this assembly, the composite assembly may become saturated with fluids. Because the weight of the food stuff sits on the underpad and because there is no distance between the food stuff and the fluid which is directly aligned with the apertures, the pressure can squeeze the fluids out of the absorptive middle layer, through the apertures and back into the food stuff. Likewise, on the upper layer of the prior art laminated bag, if the fluids created by the gathering together of the condensed vapors, achieve a point where their weight, as pulled by gravity exceeds the force of the capillary action of the fibrous absorptive middle layer holding them in check, they can fall downwardly through the apertures to the food stuff.
The primary object of the present invention is to provide a protective assembly, and specifically a protective container assembly which retards condensate from the upper section from moving downwardly into the food stuff and similarly retards liquid from being forced by pressure upwardly through apertures into the food stuff.